You can import one or two images to make your custom hand. If you only import one hand image you can use it for moving an image in (Move-in). If you set a single image hand to 'Draw' an image (as opposed to 'Morph' or 'Move-in') it will rotate as in your GIF.

When you import two (slightly different) hand images these are used for when 'Draw' is selected on the image as opposed to 'Move-in' or 'Morph'